RadGrid HeaderContext filter menu throws '_linkElement' undefined error after expand animation ends in version 2026.1.211.462
After clicking the filter icon in a RadGrid column header, the filter menu throws the following JavaScript error in the browser console:
Uncaught TypeError: Cannot read properties of undefined (reading '_linkElement')
at Object._focusFirstItem
at Object.raise_expandAnimationEnded
at Object._onExpandAnimationEnded
Environment:
- Telerik UI for ASP.NET AJAX version: 2026.1.211.462
- ASP.NET Framework: 4.8.1
- Browser: Chrome (latest)
- FilterType: default
- RadScriptManager with no custom script references
Steps to reproduce:
1. Place a RadGrid with AllowFilteringByColumn="true"
2. Run the application
3. Click the filter icon on any column header
4. Observe the JavaScript error in the browser console after the menu animation completes
Expected behavior:
The filter menu opens and focus is set on the first menu item without any errors.
Actual behavior:
The filter menu disappears visually, does not appear, and throws a JS exception when attempting to focus the first item (_linkElement is undefined)
I have updated my project to the latest version 2026.1.211.462 but when I add the speechtotextbutton, I get failed to create designer telerik.web.ui.radspeechtotextbutton
video link:- https://jam.dev/c/88c17904-c758-47ab-949c-d29b4775dc6d
After upgrading to Telerik UI for ASP.NET AJAX 2026 Q1 (2026.1.211.462) the HtmlChart Sparkline cannot initialize.
The demo page loads, but the chart is empty and the component is not usable.
The browser console shows a JavaScript initialization failure originating from the Telerik scripts.
The first error thrown is:
Uncaught ReferenceError: kendo is not defined
at Telerik.Web.UI.WebResource.axd...
Immediately after that a second error appears:
Uncaught TypeError: kendo.jQuery(...).kendoSparkline is not a function
The second error is a cascade failure because the Kendo widgets are never registered due to the first error.
Hello Telerik Team, I'm implementing HeaderContext filtering with checkbox lists on a RadGrid in a legacy ASP.NET WebForms application. Current Setup: - FilterType="HeaderContext" - FilterCheckListEnableLoadOnDemand="true" - OnFilterCheckListItemsRequested event populates checkboxes from session data Issue: Users experience 500-2000ms delay when opening filter menus (AJAX callback to server). In our production environment with slow network and high concurrent users, this creates poor user experience. Questions: 1. Is there a way to pre-populate checkbox lists during grid initialization (avoiding AJAX callback)? 2. Can we use OnItemCreated to populate checkbox lists with FilterCheckListEnableLoadOnDemand="false"? If so, what's the correct approach? 3. Is there a client-side caching mechanism for checkbox list items? 4. What's the recommended pattern for large datasets (1000+ rows) with multiple filterable columns? Environment: - Telerik.Web.UI version:v4.0.30319- .NET Framework: 4.8 - Browser: Chrome, IE11 - Grid has ~10 columns with 5 using checkbox filters Any guidance on performance optimization would be greatly appreciated! Thank you, Anurag pandey
The gantt throws Uncaught ReferenceError: kendo is not defined when clicking on the calendar picker button.
The spreadsheet throws Uncaught ReferenceError: kendo is not defined when you type in a number in the quantity field, then click to the next cell.
I've updated the Telerik library to 2026 Q1 (2026.1.211.462) and noticed a JavaScript error "ReferenceError: kendo is not defined." is thrown on the page where the RadSpreadsheet is located.
Affected Versions
- Broken: 2025.4.1321
- Working: 2025.4.1210 and earlier
Components
RadTabStrip
RadMultiPage
RadPageView
Description
When using RadMultiPage with ScrollBars="Auto" (or any ScrollBars setting), scrollbars only appear on the initially selected tab. After switching to another tab client-side, the scrollbar does not appear even when the content overflows.
The input box for RadOTPInput style are vertical lines instead of text boxes. Your demo site also has that problem, https://demos.telerik.com/aspnet-ajax/otpinput/overview/defaultcs.aspx. Should I downgrade until this is fixed? Currently on 2025.4.1321.462
Thanks,
Khanh
Please implement WAI-ARIA support in RadSearchBox with and without a Search Context. It needs the same type of logic added as the AutoComplete and ComboBox control so that JAWS can speak and navigate the list items properly. It looks like there was a little started because it renders an ARIA live region for status, but never writes to it from what I can tell. I know this document lists the current controls that support ARIA - http://docs.telerik.com/devtools/aspnet-ajax/controls/wai-aria-support-and-screen-readers Thanks, Mike
After updating to the new version, our RadListBoxes are behaving strangely. This problem is especially apparent when using a RadListBox with checkboxes that need to scroll.
When the RadListBox has enough elements and a restricted height, it lets you scroll through the items. If you check an item's checkbox, the list box appears to select the first item you can see. At that point, the item that appeared selected becomes marked or something, and you will not be able to check or select any other item in the RadListBox unless that item is visible. It also snaps the scroll position of the RadListBox back to the marked row.
We have an old local install of our project running the 2025.3.825 version, and the RadListBoxs work just fine. This issue was likely caused by a change somewhere between the 2025.3.825 and 2025.4.1321 versions.
Steps to recreate:
1. Check an item's checkbox
2. Scroll the items until you cannot see the one you checked.
3. Try to check another item's checkbox.
The InsertLink light dialog has a typo in the for attribute of the URL label, causing a case mismatch with the input's id. This results in accessibility tools like Wave and SortSite reporting the URL textbox as an unlabeled control.
Steps to Reproduce
1. Add a RadEditor with EnableAriaSupport="true" to a page
2. Ensure the InsertLink tool is enabled (it is by default)
3. Click the InsertLink toolbar button to open the dialog
4. Run an accessibility audit using Wave, SortSite, or inspect the DOM
Expected Behavior
The label's for attribute should match the input's id attribute exactly, allowing accessibility tools to correctly associate the label with the input.
Actual Behavior
• Label has for="LinkURL" (uppercase "URL")
• Input has id="LinkUrl" (mixed case "Url")
Since HTML for/id matching is case-sensitive, the label is not properly associated with the input control.
Affected File
InsertLink.ascx
When RadEditor switches to HTML mode, a `<textarea>` with class `reTextArea` is dynamically created. This textarea lacks proper accessibility attributes, causing WCAG accessibility tools (e.g., Wave) to flag it as an unlabeled form control.
## Steps to Reproduce
1. Create a RadEditor with `EnableAriaSupport="true"`
2. Switch to HTML mode
3. Run Wave or similar accessibility checker
4. Observe the textarea is flagged as "missing form label"
## Expected Behavior
When `EnableAriaSupport` is enabled, the HTML mode textarea should have:
- `aria-label` attribute to identify its purpose
- `aria-hidden="true"` when in Design mode (hidden state)
## Fix
Added ARIA attributes in `_getHtmlModeTextarea()` and toggle `aria-hidden` in `_showTextArea()` based on `EnableAriaSupport` setting.
AutoSize shows a scroll in Chrome.
See your own Window auto-size demo page
Here is a screenshot from your demo. See scroll-bars...you must slightly resize bottom right to make them disappear.
